Ball lock control valve

ABSTRACT

A control valve in which a valve seat is engaged by a closure member carried by a poppet. The poppet is mounted within a surrounding piston. A plurality of balls disposed around the periphery of the poppet engage larger circular openings in the piston to provide a limited amount of longitudinal movement of the poppet within the piston. A poppet return spring urges the closure member toward the valve seat. A strong pressure reference spring engages the piston, but its pressure is exerted against the valve body and not against the valve seat. Since the valve seat is not subjected to high pressure, it may be made narrow and sharp and only a small pressure differential is required to move the closure member from seating to sealing position.

United States Patent [191.

Whitten I 1 BALL LOCK CONTROL VALVE [75] Inventor: David E. Whitten,Northridge, Calif.

[73] Assignee: Air-Dry Corporation of America,

' Northridge, Calif.

22 Filed: May 30, 1912 211 Appl. No.:2$7,700

[52] 11.8. Cl. 137/509, l37/516.27, 251/76 [51] Int. Cl. F16]: 31/12[58] Field of Search 137/474,508, 509, l37/5l6.27, 494; 251/76, 83

[56] References Cited UNITED STATES PATENTS 2,351,190 6/1944 Carlsonl37/5l6.27 X

3,040,772 6/1962 Todd 137/509 3,073,338 1/1963 Cholvin 137/509 X [451Aug. 28, 1973 Primary Examiner-l-1arold W. Weakley Attorney-Robert C.Comstock [57] ABSTRACT A control valve in which a valve seat is engagedby a closure member carried by a poppet. The poppet is mounted within asurrounding piston. A plurality of balls disposed around the peripheryof the poppet engage larger circular openings in the piston to provide alimited amount of longitudinal movement of the poppet within the piston.A poppet return spring urges the closure member toward the valve seat. Astrong pressure reference spring engages the piston, but its pressure isexerted against the valve body and not against the valve seat. Since thevalve seat is not subjected to high pressure, it may be made narrow andsharp and only a small pressure differential is required to move theclosure member from seating to scaling position.

8 Claims, 3 Drawing Figures 'adjustingtime.

I BALL LOCK- CONTROL VALVE BACKGROUNDOF THE INVENTION 1;. Field-of theinvention The invention' relates to' a ball lockcontrol valve whichrequires aminimum amount'ofseating force.

2. Description-of the Prior Art N control'valve which:is operated by orsubjectedto high pressure forces'customarily requires a-wide valveseat-which is-capable of withstanding'such highforces.

A" wide valve seat requires high reseat forces for sealing,wh'icliiseffected'by-a large'crack to reseat'pressure differential;Excessively high seat wear unnecessarily resultsfromthe high pressureacting upon the valve seat:

SUMMARY- OFTI-IE INVENTION The invention-provides a'control-valve inwhich the high pressure. reference springsforce is taken out'in valvestructure other than the valve seat, withonly the minimum amount ofpressure being applied directly to the valve seat: Afloating poppetwhich 'is isolated from the-high pressure requires only a'minimum'amountof crack.toreseat pressure differential; This permitsuse.

of a-relatively narrower andsharper valve seat, witha reduced amount=ofseat 'wear' for longer life.

ltisaccordingly th'e primary object of the invention to provide acontrol valve structure having the advan tagesand benefits set forthabove and described hereinafter in this specification.-

Ano'tli'er object ofthe invention 'is'to provide a con trol valvewhichrequires a minimum amount of reseat used,'and which may also be usedwith seats of other materials.

Another object'isto'provide such a devicein which the number of sealsrequired is substantially reduced.

ln o'ne embodiment of the invention, the device is externally-adjustableover a'substantially'wide range of cracking pressures.

- Theinvention also comprises such other objects, ad-

1 vantages and capabilities as will later more fully appear and whichare inherentlypossessed by the invention.

YWI'IIIC: there is .shown in theaccompanying drawings apreferredembodiment of the invention, it should be understoodthat the'same issusceptible'of modification and changewithout departing from the spiritof the invention.

DESCRIPTION OF THE DRAWINGS FIG. I is a longitudinal sectional view-of acontrol valve constructed in accordance with-this invention,

withthepoppet and piston closed;

FIG; 2 is a similar partial sectional view showing the poppet and pistonin open position;

invention is to provide a in'the drawings) reciprocal movement within 'asur- DESCRIPTIONOF THE PREFERRED EMBODIMENT A preferred embodiment whichhas beenselected to illustrate my invention comprises a valve body10"having on one end thereof an internally screw threaded inlet]! and atthe other end thereof an internally screw threaded outlet 12 towhichappropriate connections may be made.

The inner end of the inlet 11- isclose'd at'its lower portion bya'vertically directed'wall 13, the uppe'rportion being open and adaptedto connect with a' passage 14 leading to theoutlet 12; The upper endofthe 'pas-" sage carries a valve seat 15, which is normallyclosed off'bya conicalclosure member 16, which comprises the lowerend of a poppet 17.

The poppet 17 is mounted for longitudinal (vertical rounding piston 18.A poppet reference spring l9"ex tends between the upper end of thepoppet .l7 and the adjacent'port ion of the piston 18: The spring 19normally urges the poppetdownwardl seat 15 to close off'the passage 14;

Aplurality of balls 20 are mounted in recesses 20a formed'in thesides'of the poppet l7. lnthe embodiment'sh own' in the drawings, fourballs'20 are utilized.

The balls-20 protrude beyondthe o'u terperipheryof the poppet l7 andtheir outer portions extend into circular openings 2lfo'rmed in thelower po'itiono'f the piston 18; The openings 21 are of somewhat greaterdiameter than the balls 20. This permitsalir'nite'd amount oflongitudinal movement of thepoppet l7 within the piston '18. Y

The balls 20 are'free to rotate and'thereby provide an extremely lowfriction connection between thepoppet l7 and piston '18. It would bepossible, however; to use other suitable forms of connection betweenthese elern'ents, such as pins, protuberances, etc.

The piston 18 is slidably mounted within a vertically directed port22'extending through the upper; portion of the-valve body 10 directlyabove the passage 14. An O-ring 23 provides a moving seal betweenthepiston l8 and the walls of the port 22. Y

The upper end of the piston 18 fits within a crownshaped recess formedin the center of an annular cup 24; The cup'24 is mounted for limitedvertical mo've-,

ment within the lower portion of a housing 25, which is threadedlysecured to the upper portion of the'valve body 10.

The. housing 25 contains a large pressure reference spring 26, the lowerportion of which engages and exerts downward pressure against the cup24. The upper end of thefspring 26 is held in place at thetop of thehousing25 by a cap 27. p

The device is shown in closed position in FIG. 1 of the drawings, withthe bottom of the piston l8'being held againstthe portion of the valvebody 10 surrounding the passage 14 by pressure from the pressurereference spring 26.

The closure member 16 comprising the lower end of the poppet 17 is inclosed sealing engagement with the valve seat 15 surrounding the upperend of the passage l4.-The balls 20 are disposed adjacent to the centerof the openings-21 because the poppet 17 cannot move y against the valveany further downwardly with respect to the piston 18 because of theengagement between the closure member 16 and valve seat 15.

An increase in the inlet pressure occurring at the inlet 1 1 acts on thearea defined by the port 22, less the area defined by the valve seat 15.

When the inlet pressure increases sufficiently to overcome the force ofthe pressure reference spring 26, the piston 18 is raised a shortdistance upwardly. As the piston 18 moves upwardly, the balls 20 areengaged by the lower edges of the openings 21 in the piston 18. This isthe limit of possible upward movement of the piston 18 with respect tothe poppet 17.

Further upward movement of the piston 18 results in upward movement ofthe poppet 17 caused by the engagement of the balls 20 with the piston18. As the poppet 17 is moved upwardly, the closure member 16 is liftedoff the valve seat 15 and flow passes from the inlet 11 through thepassage 14 to the outlet 12.

When the inlet pressure is reduced, the pressure reference spring 26exerts sufficient downward force on the cup 24 to urge the piston 18downwardly. Downward movement of the piston 18 continues until theclosure member 16 engages the valve seat 15. The poppet 17 will thenremain stationary while the piston 18 continues to move downwardly untilits lower edge engages the portion of the valve body surrounding thepassage 14.

The pressure from the pressure reference spring 26 is thus applieddirectly to the valve body 10 through the piston 18. There is nopressure exerted on the valve seat at this time or at any time by thepressure reference spring 26. The only pressure which is applied to thevalve seat 15 is the pressure exerted by the poppet return spring 19.

Since the piston 18 continues to move downwardly after the poppet 17 isstopped, the balls 20 remain stationary and the openings 21 movedownwardly so that the balls 20 are oriented approximately in the centerof the openings 21 when the lower edge of the piston 18 engages thevalve body 10.

it will thus be seen that a substantially narrow and sharp valve seatmay be used because it does not have to be made strong enough towithstand a large amount of closing pressure. Only a small amount ofpressure is accordingly required to move the closure member from touchto seal-off and only a minimum amount of seat stress is necessary forsealing.

FIG. 3 is a graph showing the pressures and pressure differentialsinvolved in the operation of the valve.

In order for the closure member to move from touching to scalingposition, it must crush the asperities of the valve seat. If the seat issharp and narrow, less pressure is required to move the closure memberfrom touching to sealing position. With this invention, the valve seatcan be made sharp and narrow because it does not have to withstand asubstantial amount of pressure. Only a small pressure differential isaccordingly required to move from seating position to sealing position.

I claim:

1. A control valve comprising a valve body having an inlet and anoutlet, a valve seat surrounding an opening controliing flow from saidinlet to said outlet, a poppet having a closure member normally engagingsaid valve 'seat, said poppet being mounted for longitudinal movementwith respect to a piston, a poppet return spring disposed betweenportions of said poppet and piston, said poppet return spring urgingsaid poppet away from said piston toward said valve seat, a pressurereference spring acting upon said piston, said pressure reference springurging said piston into engagement with said valve body, the entirepressure of said reference spring being exerted against said piston andvalve body, the only pressure exerted against said valve seat being thatof said poppet return spring, and means engageable between said pistonand poppet whereby upward movement of said piston moves said poppetupwardly to lift said closure member off said valve seat and open saidoutlet.

' 2. The structure described in claim 1, the means engageable betweensaid piston and poppet comprising at least one ball carried by one ofsaid members, said ball being movably mounted in an opening oflargerdimension formed in the other of said members.

3. The structure described in claim 2, and a plurality of balls carriedby said poppet, said balls extending into openings of larger dimensionformed on said piston.

4. The structure described in claim 3, said poppet carrying four ballsequally spaced from each other around the periphery of said poppet.

5. The structure described in claim 3, said piston being substantiallycylindrical and hollow, said poppet being cylindrical and beingreciprocally mounted within the hollow interior of said piston.

6. The structure described in claim 5, said poppet return spring beingdisposed within said piston and extending between the inside of theupper end of said piston and the upper portion of said poppet.

7. The structure described in claim 6, said piston having asubstantially circular lower edge which engages the portion of saidvalve body surrounding said valve seat.

8. The structure described in claim 7, and an O-ring carried by saidvalve body and engaging the exterior of said piston to provide a movingseal between said piston and valve body.

1. A control valve comprising a valve body having an inlet and anoutlet, a valve seat surrounding an opening controlling flow from saidinlet to said outlet, a poppet having a closure member normally engagingsaid valve seat, said poppet being mounted for longitudinal movementwith respect to a piston, a poppet return spring disposed betweenportions of said poppet and piston, said poppet return spring urgingsaid poppet away from said piston toward said valve seat, a pressurereference spring acting upon said piston, said pressure reference springurging said piston into engagement with said valve body, the entirepressure of said reference spring being exerted against said piston andvalve body, the only pressure exerted against said valve seat being thatof said poppet return spring, and means engageable between said pistonand poppet whereby upward movement of said piston moves said poppetupwardly to lift said closure member off said valve seat and open saidoutlet.
 2. The structure described in claim 1, the means engageablebetween said piston and poppet comprising at least one ball carried byone of said members, said ball being movably mounted in an opening oflarger dimension formed in the other of said members.
 3. The structuredescribed in claim 2, and a plurality of balls carried by said poppet,said balls extending into openings of larger dimension formed on saidpiston.
 4. The structure described in claim 3, said poppet carrying fourballs equally spacEd from each other around the periphery of saidpoppet.
 5. The structure described in claim 3, said piston beingsubstantially cylindrical and hollow, said poppet being cylindrical andbeing reciprocally mounted within the hollow interior of said piston. 6.The structure described in claim 5, said poppet return spring beingdisposed within said piston and extending between the inside of theupper end of said piston and the upper portion of said poppet.
 7. Thestructure described in claim 6, said piston having a substantiallycircular lower edge which engages the portion of said valve bodysurrounding said valve seat.
 8. The structure described in claim 7, andan O-ring carried by said valve body and engaging the exterior of saidpiston to provide a moving seal between said piston and valve body.